Overview

Appearance

Landoltia punctata is a tiny free-floating aquatic plant made up of individual fronds with fine roots. The roots number from 2 to 4 and up to 7. It is native to Australia and Southeast Asia. Landoltia punctata was first documented in Missouri in the early 1930’s.

Foliage

Mature fronds of Landoltia punctata appear 1.5 to 2 times longer than wide, with widths measuring from 0.04-0.12 in. (1-3 mm). Fronds range from egg-shaped to kidney-shaped. They are an intense green color. Fronds may sparkle in the sunlight as a result of their waxy cuticle. Similar native duckweed, Spirodela polyrrhiza, often has a red spot on the top of the frond.

Fruit

Landoltia punctata spreads mainly through vegetative budding from two pouches at base of the frond. New fronds often remain attached to original frond by a short stem. You often see clusters of several fronds linked together. This species may sometimes reproduce sexually, producing seed.

Ecological Threat

Landoltia punctata invades quiet waters such as ponds, ditches, swamps and backwaters. It grows very quickly in water high in nutrients, for example from run off of fertilized fields. It is sometimes used to clean waste water. It probably has been introduced multiple times, possibly through the aquarium and water garden trade. Birds and other wildlife may transport it short distances, but it desiccates quickly after removal from the water. Landoltia punctata is often seen in large, almost pure populations while native duckweeds usually occur together with other duckweed species.